Earwigs (Order: Dermaptera)

Male earwigs have curved pincers at the end of their abdomens and females have straight. This photograph is of a male Forficula auricularia

Most people are familiar with earwigs. Their liking of moist crevices and rotting vegetation often brings them into contact with humans! Gardeners tend not to like them due to their fondness for nibbling at flowers such as Dahlias. However, they are omnivorous and eat many pest species. So, on balance, they are often beneficial for gardeners.

Earwigs are a small group of insects. They are mainly tropical and Britain is at the northern extreme of their range, hence the paucity of species.

It is very uncommon for Earwigs to actually enter the ear, though they do investigate any crevice.

Main characteristics of Earwigs

Earwigs are rather elongated insects. They have simple, slender antennae and biting mouth-parts. Legs are thin and adapted for running.

The wings are not present in all species. When they are, the forewings are hardened to cover the hindwings and the base of the abdomen (most of the abdomen is always exposed). These resemble the familiar wing cases of beetles and are also called elytra.

The hindwings are almost semi-circular. They are thin and transparent. Most species hardly fly.

The abdomen ends in the characteristic pincers or cerci. The precise function of these pincers is unclear. However, some earwigs use them to intimidate predators, though some have been observed using them to fold their wings after flight.

Life-cycle

Earwigs are relatively unusual amongst insects in the care shown by the mother for her young.

Earwigs mate in late autumn.

The female usually lays 20-40 eggs in the soil and tends them over winter. She prevents fungal damage to the eggs by licking them daily.

The eggs hatch in early spring, but the young nymphs remain in their nest until they have shed a couple of skins.

The mother continues to feed and tend them even after they come above ground.

During their development, the nymphs' wings grow and the antennae gain extra segments. The cerci also gradually assume an adult form. The nymphs mature in late summer.

The commonest species in Britain is the Common Earwig (Forficula auricularia). It is about 10-15mm long and found almost everywhere.

Other species tend to be rarer, but the Lesser Earwig (Labia minor) is worth looking for. It is small (6-7mm) and flightless. It seems to like horse manure heaps!